The invention relates to a time-of-flight mass spectrometer with deflection electrodes and a micro-channel-plate detector system. The mass determination of the known time-of-flight mass spectrometers is accomplished by measurement of the individual flight times of the ions of different masses.
The deflection electrodes of such time-of-flight mass spectrometers can deflect only a whole mass range without regard for the mass-to-charge ratio of the ions. All ions passing the deflection electrodes as long as the deflection potential is switched on are deflected, don't reach the detector, and are prevented from being analysed. Ions passing the deflection electrodes during the deflection potential is switched off, can travel straight towards the detector and are analysed by determination of their flight times. The resolution of such time-of-flight mass spectrometers is limited to a few thousand for low mass ions down to a few hundred for heavy ions.
Several other types of mass spectrometers are known with higher resolution: Ion-cyclotron-resonance mass spectrometers exhibit a resolution of up to 100 million or more. Magnetic sector mass spectrometers have a resolution of approx. 10 to 150 thousand. That one of quadrupole type mass spectrometers is approx. 1 to 20 thousand. But all these types of mass spectrometers are unable to analyse masses of 50'000 dalton or above.
The time-of-flight mass spectrometers have the capability to analyse masses as high as up to several 100'000 dalton. The resolution of time-of-flight mass spectrometers is poor as compared with the other mass spectrometer types and decreases with increasing masses. There is no mass spectrometer able to resolve heavy bio-molecules, genetic engineering products, and other high mass samples with a desirable high resolution.